1. Technical Field of the Invention
The present invention relates to systems and methods for editing video streams. Segments (e.g., shots or subshots) of the video streams are represented by icons which include an image derived from one of the frames of the corresponding segment.
2. Background Art
Video recording has become extremely popular. Traditionally, video tape has been used to record video streams. A video stream is a sequence of frames. In many cases, a VCR (video cassette recorder) is used to playback the video tape. More recently, computers, such as personal computers, have been used to edit video signals. Video editing software is commercially available. For example, the Adobe Premiere™ editor sold by Adobe Systems Incorporated allows a user to edit frames of a video stream by deleting, adding, and re-arranging the order of frames. Some of the frames of the video to be edited (called source clips) are displayed serially in a row in a window on a computer display. The user selects at least some of the source clips for inclusion in an edited footage section, which is displayed below the source clips in the window. The edited video section is initially empty and added to from one or more sources.
The term “shot” is used in the present disclosure. As used herein, the term shot means a portion of a video stream representing an event or a related continuous sequence of actions. The shot may end even though the camera does not stop capturing video signals. Shots often have a particular theme. For example, in a video stream of a child's birthday party, playing a game may be one shot, singing “Happy Birthday” may be another shot, and opening presents may be still another shot, whether or not the camera stops recording between shots. Various techniques have been developed to detect the beginning and ending of shots. For example, techniques for shot detection are described in B. Yeo et al. “Rapid Scene Analysis on Compressed Video,” IEEE Transactions on Circuits and Systems For Video Technology, Vol. 5, No. 6, December 1995.
In the Adobe Premiere™ editor, not every frame of the video stream to be edited is visually displayed in the window. Rather, according to the user's designation, for example, only one frame is selected by the editor to be displayed for every N frames in the video stream or only one frame is selected for a particular time interval (e.g., one frame a second). The editor does not make a selection of which frames are to be displayed based on shots that may be included in the video stream.